Chuck.



No. 658,473. Patented Sept. 25, I900.

W. D. F. SMITH &. T. COVENTRY.

C H U C K.

(Application filed Ian. 22, 1900.)

(No Model.)

wi .5" 5% WT AW NITED STATES WILLIAM DUNSTAN FORD SMITH AND THEODORECOVENTRY, OF MAN- CHESTER, ENGLAND, ASSIGNORS TO SMITH dc COVENTRY,LIMITED,

OF SAME PLACE.

CHUCK.

SPECIFICATION forming part of Letters Patent N 0. 658.473. datedSeptember 25, 1900.

Application filed January 22, 1900. Serial No. 2,349. (No model.)

To all whom it ntay concern:

Be it known that we, WILLIAM DUNSTAN FORD SMITH and THEODORE COVENTRY,subjects of the Queen of Great Britain, residing at Manchester, countyof Lancaster, England, have invented certain new and useful Improvementsin Chucks; and we do hereby declare the following to be a full, clear,and ex act description of the invention, such as will enable othersskilled in the art to which it appertains to make and use the same,reference being had to the accompanying drawings, and to letters ofreference marked thereon, which form a part of this specification.

Our invention relates to chucks which are made to grip a bar or otherarticle to be operated upon and release the same while the chuck isrotating, and is especially applicable to centrally-fed lathe-chuckshaving conical gripping-jaws sliding into the chuck-spindle and wedgingagainst the Work, being an improvement on the inventiondescribcd'in-British Letters Patent No. 13,146, dated June 11, 1698, andgranted to Theodore Coventry.

In order that our invention may be fully understood, reference will bemade to the accompanying drawings, in which like parts are similarlydesignated, and in which Figure 1 shows in perspective so much of thehead-stock of a lathe as will be necessary to a full understanding ofthe invention, with the improved chuck attached, some of the parts beingshown in section. Fig. 2 is a perspective in section, showing amodification of the sleeve d.

a is a portion of the lathe-bed, on which the head-stock slides, and bis that portion of the stock that carries the front end or nose 0 of thespindle, which is made tubular or partly tubular, as requirementsdemand. In that portion of the nose 0 of the spindle projecting beyondthe support I) are milled short longitudinal grooves 0 intersected bygrooves c. A portion of the front end of this spindle is bored conical,into which fit the grippingjaws 0, whose outer surfaces have,preferably, the same pitch as the conical part of the spindle-bore andwhose inner gripping-surfaces are shown as cylindrical. These jaws c areprovided on their outer ends, which project beyond the nose of thespindle c, with grooves c or their equivalents.

In the grooves 0 which are preferablyone hundred and twenty degreesapart, are the double toggle-levers e, whose trunnions 6 work in theslots c and prevent longitudinal displacement of these levers, whileallowing them to rock freely.

Over the nose of the spindle c is fitted an axially-movable sleeve 61,provided with an inwardly-projecting internally-threaded flange d'.Sci-owing into this flange 01' is an adjusting-ring d, which is of anydesired width, accordingv to the limit of adjustment required to begiven to the jaws. This ring is shown provided with a flange d thattakes into the grooves 0 Holes (I serve for the insertion of a suitablekey to turn said ring, whereby the jaws are set farther in or out inorder to vary the size of the central opening or the grip.

On or near the end of the sleeve 01 is turned a threaded shoulder 1 onwhich is screwed an abutment-ring (1 held in place by the setscrew 61which allows of adjustment. However, this ring can be advantageouslymade solid with the sleeve 61, as shown at (Z Fig. 2, in which case theslots (1 do not end at the edge of the sleeve (1, as shown in Fig. 1,but are simply oblong slots ending at the bead (Z Fig. 2. These slots dwhen not extend ing to the rear end of the sleeve leave a rear wall forengagement by the lovers 6, which was otherwise formed by the ring d andthese slots or perforations register with the milled slots 0 in thespindle, in both of which the double toggle-lever moves. 1n the middleof each slot d there is a cross-s1ot d corresponding to slots 0 Thiscross-slot is to allow the toggles e to be placed in position when thesleeve cl is in the center position before the collar f, hereinaftermentioned, is placed in position.

Rotatable and axially movable on the sleeve (1 is a collar f, having anexternal groove f and an internal groove f on either side ofan internalcentral flange f to receive the ends of the toggle-levers e and allowfree movement when necessary.

Projecting from the head-stock b of the lathe are two brackets b betweenwhich is pivoted, by means of the pin 9 a forked lever, whose fork gcarries in the perforated ends of its arms swivel-lugs g, held in placein said arms by nuts g and which take into the external groove f to giveaxial motion to the collar f, while permitting rotation of the same. Theother end of the lever g is connected bya link g to a bell-crank levercomprising the operatinglever g keyed to a shaft 9 journaled in thehead-stock. Also keyed to this shaft g at a suitable angle with theoperating-lever is another lever 9 whose opposite end is pivoted in theforked end of the link The angle that the lever 9 makes with the link 9is large, so that when the mechanism has been thrown to close the jawsand grip the work the lever g and link g will be nearly in alinement, soas to get as much leverage as possible.

The operation is as follows, supposing the parts to be in the positionshown in the drawings: The operating-lever g is moved in the directionof the arrow, thus bringing the lever 9 and link 9 more into alinementto give a toggle action and force the end g of the forked lever g in anopposite direction, thereby moving the fork in the same direction as theoperating-lever and carrying the collar f with it, whereby the internalflange f on 001- lar f forces the rear ends of the double toggle-leversdown against the ring or abutment d, so as to move the sleeve d in thesame direction, which carries with it the adjustingring (Z and the jawsc. The conical jaws being forced into the conical bore of the spindleare crowded together, decreasing the diameter of the central openingbetween them, and wedged between the work and the spindle, thus makingvery efficient jaws. As shown, the motion of the conical jaws into theconical bore, hence the degree of wedg-' ing action of the jaws, islimited by the longitudinal motion of the sleeve, jaws, andadjusting-ring, and in order to adjust these jaws to hold work ofvarying diameters they are moved into or out of the conical bore of thespindle; but the limit of throw of the actuating parts is not variedthereby, though this can be done when using an abutmentring d", whichwhen screwed in or out will necessarily vary to a small extent theeffective movement imparted by the double toggles. This variation ofthrow is, however, practically of little importance when an adjustmentof the jaws will accomplish a similar result. Besides it is not alwaysconvenient to adjust from the rear of the chuck, and we therefore preferto do away with this ring, as shown in Fig. 2, and adjust entirely fromthe ring (1 which is easy and convenient of access. It is also obviousthat the flange d may be omitted and the ring (I screwed into the end ofthe sleeve d. A reverse movement of the operating-lever g will cause amovement of the parts in an opposite direction to that describedabove,whereby the flange f 4 will force the front end of thetoggle-levers 8 into engagement with the front walls of the slots (1 tomove the sleeve (1 and jaws c outward and disengage the latter.

Having thus described our invention, what we claim as new therein, anddesire tosecure by Letters Patent, is-

1. In a chuck, the combination with a hollow spindle and a plurality oftapered gripping-jaws cooperating therewith; of a sleeve longitudinallyslidable on the spindle, and a ring adjustable in said sleeve andarranged to positively move the jaws into and out of the spindle,substantially as set forth.

2. In a chuck, the combination with a hollow spindle and a pluralityofgripping-jaws' cooperating therewith; of a sleeve and an external beadon its rear end integral therewith, a plurality of slots ending at thebead, mechanism for reciprocating the sleeve, and an annular flangedadjusting-ring adapted to engage grooves in the jaws and positively movethe jaws into and out of the spindle, substantially as set forth.

3. In a chuck, the combination with a hollow spindle, a sleeve thereon,slots therein and toggle-levers in said slots to slide the same; of aplurality of tapered grooved gripping-jaws in the spindle end, a ringexternally threaded and adjustable in the end of said sleeve,'and aninternal flange between the ends of said ring, said flange engaging thegrooves in the jaws, substantially as set forth.

4. In a chuck, the combination with a hollow spindle, of a sleeveprovided with an external bead on one end, longitudinal slots ending atthe base-of the bead, double togglelevers in said slots whose ends slideagainst the ends of said slots to move the sleeve, an internal threadedflange on the other end of said sleeve, conical-surfaced jaws,peripheral grooves therein, a threaded adjusting-ring in said internalflange, a flange in said ring adapted to engage the grooves in the jawsand hold and adjust the same, and mechanism for moving the levers,sleeve, ring and jaws, substantially as described.

In testimony that we claim the foregoing as our invention we have signedour names in presence of two subscribing witnesses.

WILLIAM DUNSTAN FORD SMITH. THEODORE COVENTRY.

Witnesses:

PETER J. LINSEY, WILLIAM FAULKNER.

